Q: Is the Priory of Sion an ancient, secret society designed to guard Christianity's darkest secret? A: No. The Priory of Sion was founded in 1956 by a French con artist.
The Da Vinci Code states that the Priory of Sion was founded in Jerusalem in 1099 A.D. by a French king named Godefroi de Bouillon. The book alleges that this secret society was founded in order to protect a powerful secret about Christ - one that was backed up by documents that were so explosive that the church would stop at nothing to get them (Brown, D., 2004, p. 167).
The Priory of Sion was a real organization, however, it was founded in 1956 by a French con artist named Pierre Plantard - not in 1099 by Godefroi de Bouillon. "The Priory of Sion was dissolved sometime after October, 1956, but intermittently revived by Plantard who was imprisoned three times for various offenses" (Thomas, J., 2006).
A far cry from protecting a powerful secret about Christ, "Plantard originally hoped that the Priory of Sion would become an influential cryptopolitical quasi-masonic lodge (similar to the P2 cabal) dedicated to the restoration of chivalry and monarchy, which would promote Plantard's own claim to being a legitimate pretender to the throne of France" (wikipedia.org, 2006, Priory of Sion).
References:
Brown, D. (2004). The Da Vinci Code, Special Illustrated Edition. (p. 167). New York, NY: Doubleday.
Thomas, J. (2006). The Da Vinci Code. Hatfield, PA: Biblical Seminary.
Wikipedia.com. (2006). Priory of Sion. Retrieved May 14, 2006, from http://en.wikipedia.org/wiki/Priory_of_Sion.